United Nations relief officials are pleading with Saudi Arabia to stop targeting the main international airport in Yemen, saying airstrikes have destroyed runways and left them useless.

"Without access to the airports, aid agencies are unable to bring in staff, vital supplies of medicines and other critical life-saving assistance, or undertake medical evacuations of their personnel," said U.N. relief coordinator for Yemen, Johannes van der Klaauw.

He called the international airport in Sana'a an important lifeline, along with all the country's air and seaports.

Heavy Saudi-led airstrikes targeted several airports Monday across Yemen. The airstrikes are targeting Shiite rebels, known as Houthis, who are locked in fierce fighting against forces loyal to exiled President Abed Rabbo Mansour Hadi.

Meanwhile, Secretary of State John Kerry will visit Riyadh for discussions with Saudi government leaders on Wednesday and Thursday.

The U.S. is pushing for a "humanitarian pause" in the fighting in Yemen that would allow much-needed food, fuel and humanitarian supplies to be delivered to the country and transported to places of greatest need.

Saudi Foreign Minister Adel al-Jubeir said Monday that coalition countries were considering a cease-fire to allow the delivery of humanitarian aid.

The State Department said Kerry plans to hold follow-up talks with officials from Saudi Arabia and other Gulf Arab states in Paris after his trip to Riyadh.

U.N. relief workers in Yemen say a lack of fuel has forced humanitarian partners to suspend food aid in some districts. They also say they are hindered by insecurity caused by Saudi coalition airstrikes against the Iranian-backed Houthi rebels.

The U.N. said more than 1,200 people have been killed and 300,000 forced to flee their homes in the past two months in Yemen.

The Saudi-led Arab coalition is targeting the Houthis to try and fully restore the internationally-recognized President Abdu Rabu Mansour Haidi to power.